I sent a package via courier in India which customs found a very small amount of a white powder that they say is a drug. They have my name, address, passport number, visa number.
I am no longer in India but not in the US.
The courier requested I send a copy of my visa and passport to them prior to informing me of what customs had found.
Customs has not contacted me.
What actions can I expect from the customs of India?

Well the fact the courier asked for copies of OP visa and passport prior to informing OP of what customs found is a huge red flag. If anything customs would ask the courier for OP contact info and contact OP directly. I don't know Indian customs procedures but this would just seem logical to me.